25-11-2016, 08:08 PM
(This post was last modified: 25-11-2016, 08:10 PM by Mike Watterson.)
Mind you, my 1935 HMV radiogram is a moving iron magnetic cartridge!
http://www.radiomuseum.org/r/hismasters_370.html
The moving iron Pickup coil uses unbelievably fine wire, with about 42500 Ohms (42K5!) on about a 15mm bobbin about 5mm tall winding. It was open circuit, but it was where the internal bobbin wire connected to lead out wires had corroded, so I was able to replace them!
The "moving iron" isn't the steel needle, but a bit of metal attached to the needle holder. I found a bamboo "needle" worked very well.
It's a very heavy assembly.
If I was connecting an SP25 deck to a valve amp, I'd be tempted to use a ceramic cartridge?
Certainly it's nearly 40 years since I assembled DIY decks & cartridges, so don't listen to me. I have a Dual 55, and I presume it has the correct cartridge as it came from a deceased BBC Recording Engineer that became a Lawyer (before he died).
http://www.radiomuseum.org/r/hismasters_370.html
The moving iron Pickup coil uses unbelievably fine wire, with about 42500 Ohms (42K5!) on about a 15mm bobbin about 5mm tall winding. It was open circuit, but it was where the internal bobbin wire connected to lead out wires had corroded, so I was able to replace them!
The "moving iron" isn't the steel needle, but a bit of metal attached to the needle holder. I found a bamboo "needle" worked very well.
It's a very heavy assembly.
If I was connecting an SP25 deck to a valve amp, I'd be tempted to use a ceramic cartridge?
Certainly it's nearly 40 years since I assembled DIY decks & cartridges, so don't listen to me. I have a Dual 55, and I presume it has the correct cartridge as it came from a deceased BBC Recording Engineer that became a Lawyer (before he died).
